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Re: Struct and Union

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"Rick C. Hodgin" <rick.c.hodgin@gmail.com> writes:

> On Friday, July 10, 2015 at 6:45:34 PM UTC-4, Ben Bacarisse wrote:
>> "Rick C. Hodgin" <rick.c.hodgin@gmail.com> writes:
>> <snip example of making a "discriminated union" in C>
>> 
>> > That being the case, the OP should use C++ then and make it a class
>> > with encapsulated accessors.
>> 
>> The OP should *consider* using C++, but saying that they should use C++
>> is too strong.
>
> I think the OP should use the method I suggested, a union structure,
> with the identifer member. :-)

That *and* C++!  You sure know how to tell people what they should do,
don't you? :-)

> But if he's going to use your suggestion, then it makes much more
> sense to use a class and the encapsulation it affords.

If the OP did that they would not be using my suggestion.  My suggestion
was about what to do in C.

>> This is one of those places where, from the C programmer's point of
>> view, you have to keep reinventing the wheel.  This problem was solved
>> decades ago (see, for example, Algol 68) and solved again and again in
>> various ways every few years or so since.  But all of these solutions
>> are just a shade above the level that C is pitched at in terms of
>> programming abstractions.
>
> I would not call it reinventing the wheel.  Certain abilities in
> code are fundamental, and we will all arrive at them when considering
> how best to handle a situation.  The OP has come up with two
> solutions, and there are several others which would serve this cause.
> In my view, none of them are re-inventing the wheel, they're just
> assessing which one is best in this case for this app.

None of the C suggestions really solve the problem.  A solution would
help the programmer write error-free code, and the proffered options
only help a little towards that goal.  So, yes, re-inventing the wheel
is the wrong phrase -- it's more like re-inventing part of a wheel-like
thing that is almost round.

> I still choose my suggestion. :-)  Though, if C had the simple class,
> I would go with that one.

... and if C had a discriminated union I'd go with that, and if it had
type-classes (not the same as object classes) I'd go with those.  There
are lots of things the OP can't use in C -- no need to limit your
suggestions to just one thing they can't use in C.

-- 
Ben.

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Struct and Union janus <emekamicro@gmail.com> - 2015-07-10 00:49 -0700
  Re: Struct and Union Richard Heathfield <rjh@cpax.org.uk> - 2015-07-10 09:04 +0100
    Re: Struct and Union janus <emekamicro@gmail.com> - 2015-07-10 01:40 -0700
      Re: Struct and Union Richard Heathfield <rjh@cpax.org.uk> - 2015-07-10 09:50 +0100
        Re: Struct and Union Richard Heathfield <rjh@cpax.org.uk> - 2015-07-10 13:44 +0100
    Re: Struct and Union "Bill Davy" <Bill@SynectixLtd.com> - 2015-07-10 12:37 +0100
      Re: Struct and Union Keith Thompson <kst-u@mib.org> - 2015-07-10 08:24 -0700
        Re: Struct and Union Keith Thompson <kst-u@mib.org> - 2015-07-12 12:53 -0700
  Re: Struct and Union Ian Collins <ian-news@hotmail.com> - 2015-07-10 21:32 +1200
  Re: Struct and Union "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-10 05:12 -0700
    Re: Struct and Union Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-07-10 17:35 +0100
      Re: Struct and Union David Kleinecke <dkleinecke@gmail.com> - 2015-07-10 10:18 -0700
        Re: Struct and Union "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-10 10:23 -0700
        Re: Struct and Union James Kuyper <jameskuyper@verizon.net> - 2015-07-10 13:47 -0400
        Re: Struct and Union Keith Thompson <kst-u@mib.org> - 2015-07-10 12:38 -0700
      Re: Struct and Union "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-10 10:27 -0700
  Re: Struct and Union Bartc <bc@freeuk.com> - 2015-07-10 13:55 +0100
  Re: Struct and Union Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-07-10 21:48 +0100
    Re: Struct and Union "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-10 13:51 -0700
      Re: Struct and Union Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-07-10 23:45 +0100
        Re: Struct and Union "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-10 17:43 -0700
          Re: Struct and Union Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-07-11 13:04 +0100
            Re: Struct and Union "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-11 05:15 -0700
              Re: Struct and Union Bartc <bc@freeuk.com> - 2015-07-11 14:01 +0100
                Re: Struct and Union "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-11 06:05 -0700
                Re: Struct and Union "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-07-11 06:13 -0700
            Re: Struct and Union Keith Thompson <kst-u@mib.org> - 2015-07-11 13:51 -0700
              Re: Struct and Union Martin Shobe <martin.shobe@yahoo.com> - 2015-07-11 16:51 -0500
              Re: Struct and Union Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-07-11 23:13 +0100
                Re: Struct and Union Keith Thompson <kst-u@mib.org> - 2015-07-11 17:39 -0700
              Re: Struct and Union Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-11 16:56 -0700
  Re: Struct and Union Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-10 18:52 -0700
  Re: Struct and Union Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-10 19:12 -0700

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